While some environmental groups say Maryland's municipal stormwater permits are too vague, the state's highest court has ruled the permits are legal.

The permits issued by the Department of the Environment comply with the federal Clean Water Act, according to a ruling filed Friday by the Maryland Court of Appeals.

"Citizens want to know the state and county are reducing this pollution," said Tom Zolper, a spokesman for the Chesapeake Bay Foundation, one of the lawsuit complainants. "We wanted tougher permits to make sure that happens. The court has denied these tougher permits. That's disappointing."

The case, brought against MDE by several environmental and riverkeeping organizations, upheld lower court rulings that supported the legality of the municipal permits for Anne Arundel, Baltimore, Montgomery and Prince George's counties, as well as Baltimore City.

With these permits, "each jurisdiction is required to treat or reduce 20 percent of its impervious surface area during the course of the permit and take other specified actions," according to MDE. The EPA's stormwater regulations through the National Pollutant Discharge Elimination System require large urban areas to control stormwater pollution to the "maximum extent practicable."

But MDE said the current system is effective. Environment Secretary Ben Grumbles called the ruling a "big win" for the bay and the watershed.

"The ruling supports our approach of combining accountability with flexibility to help local governments find practical solutions to reducing polluted stormwater runoff," he said.

Maryland first issued stormwater permits in 1993. Permits are updated every five years

Erik Michelsen, the administrator of the county's Watershed Protection and Restoration Program, said the system upheld by the court combined with "total maximum daily load" pollution limits keep the county's feet to the fire.

"There are multiple levels of reporting we're held to that are subject to public scrutiny," he said.

But with Anne Arundel County's permit term ending 2019, Michelsen said, "I don't think it's too soon to be having a discussion about what those permits will look like."